feat: add support for different kubectl versions (#4)

README.md

@@ -26,6 +26,7 @@ jobs:
       uses: steebchen/kubectl@master
       env:
         KUBE_CONFIG_DATA: ${{ secrets.KUBE_CONFIG_DATA }}
+        KUBECTL_VERSION: "1.15"
       with:
         args: '"rollout status deployment/my-app"'
 ```
@@ -38,4 +39,8 @@ jobs:
 cat $HOME/.kube/config | base64
 ```
 
+## Environment
+
+`KUBECTL_VERSION` - (optional): Used to specify the kubectl version. If not specified, this defaults to kubectl 1.13
+
 **Note**: Do not use kubectl config view as this will hide the certificate-authority-data.

entrypoint.sh

@@ -6,4 +6,4 @@ set -e
 echo "$KUBE_CONFIG_DATA" | base64 --decode > /tmp/config
 export KUBECONFIG=/tmp/config
 
-sh -c "kubectl $*"
+sh -c "kubectl${KUBECTL_VERSION:+.${KUBECTL_VERSION}} $*"